I’ve mentioned here before the hypothesis, proposed by Dr. Richard Wrangham, Professor of Biological Anthropology at Harvard University, that cooking is not only a distinctly human trait, but also a practice that helped shape human evolution. The idea is that, because cooking makes nutrients in food more accessible with less effort, the switch to cooked food made it easier to support our big, metabolically expensive brains. One key question about the hypothesis is a historical one: did the routine use of fire for cooking precede or follow the anatomical changes that mark modern humans?
The BBC News site has a report on some new research [abstract], published in the Proceedings of the National Academy of Sciences, that may shed some additional light on the question. A team of researchers from South Africa, Canada, the US, Israel, and Germany explored the Wonderwerk Cave in the Northern Cape province of South Africa, and found sediment layers containing burned bone and ashes from plants, dating back approximately 1 million years. Other evidence indicates that our ancestor Homo erectus used the cave.
Stone tools found at Wonderwerk Cave indicate the ancestor in question may have been Homo erectus, a species whose existence has been documented as far back as 1.8 million years ago.
The fire residue was found approximately 30 meters inside the cave entrance, making it unlikely to be the result of a wildfire spreading from the outside. There is also evidence that fires occurred multiple times at the same spots. (The complete paper is available here [PDF].) If the results hold up under scrutiny, they will push back the earliest date of confirmed use of fire by about 300,000 years.
In an article on this research at the New Scientist, Dr. Wrangham says that the results are most interesting, but need further exploration.
Wrangham calls the work an “exciting breakthrough”. “There are other sites in Africa, more than 1 million years old, that now bear re-examination,” he says.
This evidence is not conclusive proof of Wrangham’s idea, of course, but it does suggest that some of our ancestors may have been more advanced than perhaps we thought.